Photocatalytic concrete products

Practical application and modeling

Fig. 1 Influence of red pigments on the NO degradation rate:
no pigment (n.P.); 2% pigment type 1 (2% P1); 2% pigment type 2 (2% P2); 5% pigment type 1 (5% P1).

Fig. 2 Agglomerates of TiO₂ formed at the surface of a concrete paving block.

Fig. 3 NO degradation rates of tested paving blocks produced on industrial scale.

Fig. 4 Regression analysis of experimental data presented in [8] (left) and data taken from [9] (right).

Fig. 5 NO degradation versus present UV-A irradiance for an outside measurement.

Fig. 6 Influence of the UV-A irradiance E on the reaction rate constant k and the adsorption equilibrium constant K_d.

Fig. 7 Influence of the relative humidity on the NO degradation rate.

Fig. 8 Influence of relative humidity RH on the reaction rate
constant k and the adsorption equilibrium constant K_d.

Fig. 4: Regression analysis of experimental data presented in [8] (a) and data taken from [9] (b).

The air quality in inner-city areas remains a major problem for the future. Promising solutions are available by the use of air-purifying concrete products since available filters for particulate matters are not affecting the emission of nitrogen oxides. An effective application of air-purifying concrete products requires knowledge both on the theoretical background of the photocatalytic reaction as well as their practical application. These will be addressed in the present article.

However, the overall interest on air quality in inner-city areas will increase as rising traffic rates will cause a number of conflicts with the limiting values given by the European Council [1]. The exceed of critical values is expected in densely settled areas, caused by the reduction of already existing thresholds till 2010 on the one hand and increasing traffic rates, especially for diesel powered passenger cars and freight vehicles, on the other hand. The application of filters reduces the emission of particulate matter originated by diesel powered vehicles but does not effect the...